The following disclosure relates to radar modules for providing ultra-wide angular field of view (FOV) coverage.
Radar technology has increasingly been used in numerous applications in consumer products. For example, radar systems have been incorporated into cars and other vehicles to provide parking assistance systems, collision avoidance systems, and air bag deployment systems (pre-crash detection). Depending upon the particular task being performed by the radar, vehicle-mounted radar systems may need to provide information regarding obstacles that may be within a range of distances (e.g., 1 to 100 meters), and any angular position around the vehicle.
With regard to FIG. 1A, a conventional baseline radar module 100 may be configured with a single antenna. This configuration may provide an azimuthal FOV 102 of ±70°. This 140° module 100 facing northward from vehicle 104 in FIG. 1A can be seen providing limited coverage. FIG. 1B shows another typical arrangement, in which vehicle 104 uses four radar modules 106A-106D to cover the front, rear, left and right side quadrants of vehicle 104 in order to provide a nearly complete surround coverage. However, even the use of four modules may not achieve full azimuthal coverage (see uncovered regions 108A-108D.)
Certain vehicle blind spot detection/monitoring systems implement one broad radar transmit pattern and an array of receivers. The narrow receiver beams are either steered or formed digitally, and scan the area of interest. This approach has the disadvantage of requiring multiple analog receiver circuits, which can be of relatively high-cost. In other systems, a single broad transmit antenna is used for short range, and several, e.g., four, separate receivers are used to enable digital beam forming. These approaches to digital beam forming can also add substantially to the cost of the radar system.
Furthermore, some applications (e.g., automotive radar) have relatively difficult design parameters, including restrictions on the physical size of the radar system, in addition to minimum operational performance requirements. Competing design requirements (e.g. low cost, small size, high performance parameters) can make the design of such radar systems relatively challenging. Among the design challenges is the challenge to provide an antenna system which meets the design goals of being low cost, compact and high performance.
Thus, it would be desirable to provide a compact radar module that provides a cost effective approach to obtaining relatively high performance characteristics, including an ultra-wide azimuthal FOV.